Computer operating systems offer numerous ways of registering applications to be launched when the computer is powered up or when users are logged on. These startup applications can be a major cause of performance issues at boot (power-up) and at logon time. At install time, software applications often register themselves as startup applications without considerations of whether that is necessary for the user. The users often are confused and don't know how to turn off this option, the end result being a large number of startup applications on the average user's machines that take a long time to initialize. During this initialization, they consume system resources on the machine, even though most of them are unnecessary or unwanted by the user immediately and can be started at a slower pace. A large number of Microsoft Windows customers have to wait a long time to be able to start using their computer after logging on because of this issue. Of course, there are startup applications that are necessary and important such as instant messenger, anti-virus, or anti-spyware applications.